Equilateral and Isosceles Triangles

Front

What is an equilateral triangle?

Back

A triangle with all three sides of equal length and all three angles measuring 60°.

Front

What is an isosceles triangle?

Back

A triangle with at least two sides of equal length and the angles opposite those sides are equal.

Front

What is the sum of the interior angles of a triangle?

Back

The sum of the interior angles of any triangle is always 180°.

Front

If two angles of a triangle are 50° and 80°, what is the measure of the third angle?

Back

The third angle measures 50°.

Front

In an isosceles triangle, if one angle is 40°, what are the measures of the other two angles?

Back

The other two angles each measure 70°.

Front

What is the relationship between the sides and angles in a triangle?

Back

The larger the angle, the longer the opposite side; the smaller the angle, the shorter the opposite side.

Front

How do you find the missing angle in a triangle?

Back

Subtract the sum of the known angles from 180°.

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.

Front

What is a scalene triangle?

Back

A triangle with all sides of different lengths and all angles of different measures.

Front

If a triangle has angles measuring 72°, 72°, and x°, what is the value of x?

Back

x = 36°.